1. Technical Field
The present disclosure relates generally to Orthogonal Frequency Division Multiplexing (OFDM) symbol detection in a multiple input multiple output (MIMO) system.
2. Background Art
One disadvantage of conventional tree-based detection algorithms for multi-carrier modulated signals (e.g., OFDM) (with multiple antennas at the transmitter transmitting multiple spatial layers and multiple antennas at the receiver) is that the detection time can vary significantly from one tone to another due to varying channel conditions. For hardware implementation purposes, this is problematic because if the actual detection time varies from tone to the next tone, the detection throughput will be non-constant. One approach to solve this problem sets a fixed limit on the number of nodes that the tree detector can visit for a given tone. If the detector is able to complete detection within this fixed limit, it will return an optimal solution (e.g., Maximum Likelihood (ML) solution). Otherwise, the detector returns a best-effort sub-optimal solution determined up to that point. A disadvantage of this approach is that it does not adapt the fixed limit from tone to the next tone and does not exploit the time slack of early terminating detectors.
The present disclosure will be described with reference to the accompanying drawings. Generally, the drawing in which an element first appears is typically indicated by the leftmost digit(s) in the corresponding reference number.